Safety apparatus for extrusion press dummy block



Nov. 1, 1966 w. ZHOOKOFF 3,282,075

SAFETY APPARATUS FOR EXTRUSION PRESS DUMMY BLOCK Filed July 5, 1963 Q v Q! a BYWALTE'R zgjgl/ ATTORNEY United States Patent 3,282,075 SAFETY APPARATUS FUR EX'IRUSION PRESS DUMMY BLOCK Waiter Zhookolf, Swarthmore, Pa, assignor to BaldwinlLirna-ltlamilton Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed July 3, 1%3, Ser. No. 292,614 3 Claims. (Cl. 72-21) In general, this invention relates to new and improved safety apparatus for extrusion presses and more particularly for apparatus useful in determining the absence or misalignment of a dummy block preparatory to the extrusion of a billet.

Extrusion apparatus is extremely expensive, and damage thereto can be costly in terms of repair and lengthy shutdown of the extrusion press. Dummy blocks are utilized to protect the main extrusion stem from the hot metal and also to prevent sticking of this molten metal to the extrusion stem after completion of the extrusion stroke. The dummy block must be correctly aligned in order to provide uniform pressure to the billet as it is extruded within the container.

In the past, air pressure-type sensing units have been utilized to sense the correct positioning of the dummy block within the container. However, these are extremely difficult to maintain, require a source of air pressure, and are expensive to install.

Therefore, it is the general object of this invention to avoid and overcome the foregoing and other difficulties of prior art practices by the provision of a new and improved safety apparatus for use with extrusion presses.

Another object of this invention is the provision of better safety apparatus for extrusion presses capable of determining the absence or presence of a dummy block prior to extrusion.

Still another object of this invention is the provision of a new and better safety apparatus for extrusion presses capable of determining misalignment or misplacement of a dummy block.

A further object of this invention is the provision of new and better safety apparatus for extrusion presses which will automatically shutoff the extrusion press if the dummy block is misaligned or absent from its normal position.

Other objects will appear hereinafter.

In FIGURE 1, there is shown a partial cross-sectional view of extrusion apparatus incorporating the features of the present invention.

FIGURE 2 is an enlarged cross-sectional view of the dummy block and stem of the extrusion apparatus of FIGURE 1.

For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

In FIGURE 1, there is shown extrusion apparatus built in accordance with the principles of the present invention and generally designated by the numeral 10. The apparatus It includes a container 12 having a suitable die 14 at one end thereof through which a billet I6 is to be extruded. The billet 16 is placed Within the container 12 and has its rear face I8 abutting a dummy block 20. The die 14 is placed within a suitable die guide 22.

The dummy block 26 is held against the billet 16 by a suitable extrusion stem 26. The extrusion stem 26 is mounted for movement with a suitable moving crosshead 23 which is powered from the main extrusion ram 30.

In normal operation, the dummy block 20 is placed with its Working face 32 adjacent the back face 18 of the billet I6 within the container 12. The extrusion stem 26 ice is then forced forward by the main ram 30 to extrude the billet l6 through the die 14. The dummy block 20 prevents the flow of hot metal from the billet 16 towards the extrusion stem 26. Further, after the extrusion is completed, the extrusion stem 26 can be returned to its initial position without metal sticking thereto. The metal at the butt end of the billet 16 can only stick to the face 32 of the dummy block 20.

In order to insure the effective placement of the dummy block 20, safety apparatus has been provided to insure correct alignment thereof.

This safety apparatus includes the sensing rod 34 passing through a suitable bore 36 in the extrusion stem 26. The rod 34 has a cam surface 38 at the end thereof adjacent the main ram 3i and within an extension 40 of the main ram. Passing through the extension 40 is a trip rod 42 having its lower end 44 guided on the carnmed surface 38 of the rod 34. The rod 34 is spring biased by means of spring 46 to a forwardmost position. At the face 48 of the extrusion stem 26, the rod 34 has secured thereto a suitable projection 50. The projection 59 is adapted to fit with small clearances within a recess 52 formed in the dummy block 29. The projection St) is the male complement of the female recess 52.

The trip rod 42 is connected to a suitable switch 54 connected to the main power source of the extrusion press. In normal operation, the rod 34 is in a position shown in FIGURES 1 and 2. That is, the lowermost end 44 of the trip 42 is in its lowest position due to the shape of the cammed surface 38. The spring 46 maintains the rod 34 in this position. If the dummy block 20 is in the correct position as indicated in FIGURE 2, the male projection 5i) fits within the female recess 52 on the dummy block 20 and the extrusion stem 26 will extrude the billet 16 without varying the position of the trip rod 42 with respect to the cammed surface 38.

Should the dummy block 20 be absent, the male projection 59 would abut the rear surface 18 of the billet I6 forcing the rod 34 to the right. This would cause the lowermost end 44 of the trip rod 42 to ride upwardly on the cammed surface 38 tripping the switch 54 and shutting off the power to the extrusion press. In this way, no extrusion can take place if the dummy block 20 is absent.

The same action occurs should the dummy block 20 be reversed with its working surface 32; abutting the end face 48 of the extrusion stem 26. In this position, the face 32 would force the male projection 50 inwardly causing tripping of the switch 54 in the manner discussed previously.

Thus, the safety apparatus of the present invention can detect in a simple and easy manner with positive action the absence of the dummy block 20 or its misalignment in the container 12. Further, this is done without the need for special air pressure devices or other apparatus which might be subject to breakdown at any time. By this simple mechanical means, applicant has detected the presence, absence, or misalignment of the dummy block in a simple manner which will prevent costly shut-downs of the extrusion apparatus and losses due to poorly extruded billets.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

Iclairn:

1. Safety apparatus for extrusion presses comprising an extrusion stem, a dummy block having a working face and an extrusion stem receiving face on opposite sides thereof, said dummy block extrusion stem receiving face having a recess therein, sensing means carried by said extrusion stem for sensing the correct position of said dummy block, said sensing means including a first rod slidable in said extrusion stem, said first rod including a projection at one end thereof, means for biasing said first rod to an outward position, said projection being adapted to fit in said recess when said first rod is in said outward position, said first rod also including a laterally outwardly facing cam surface adjacent the other end thereof, said sensing means further including a trip rod, said trip rod being slidable in a direction generally perpendicular to said first rod, a cam follower portion rigidly disposed on one end of said trip rod and in slidable engagement with said cam surface so that movement of said first rod is transmitted directly to said trip rod, and means responsive to movement of said trip rod to provide a signal indicative of improper dummy block position.

2. Apparatus in accordance with claim 1 wherein said means for biasing said first rod to said outward position References Cited by the Examiner UNITED STATES PATENTS 2,736,429 2/1956 Sejournet et a1. 207-10.21 2,925,176 2/1960 Wyngaret 2079 2,976,991 3/1961 De Matteo 207-13 3,014,583 12/1961 Huffman et al 207-2 CHARLES JV. LANHAM, Primary Examiner. MICHAEL V. BRINDISI, Examiner. E. D. OCONNOR, H. D. HOINKES,

Assistant Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,282,075 November 1, 1966 Walter Zhookoff It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the printed specification, lines 4 to 6, for "assignor to Baldwin-Lima-Hamilton Corporation, Philadelphia, Pa. a corporation of Pennsylvania" read assignor, by mesne assignments, to Baldwin-Lima-Hamilton Corporation, Philadelphia, Pa a corporation of Delaware Signed and sealed this 5th day of September 1967.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesfing Officer Commissioner of Patents 

1. SAFETY APPARATUS FOR EXTRUSION PRESS COMPRISING AN EXTRUSION STEM, A DUMMY BLOCK HAVING A WORKING FACE AND AN EXTRUSION STEM RECEIVING FACE ON OPPOSITE SIDES THEREOF, SAID DUMMY BLOCK EXTRUSION STEM RECEIVING FACE HAVING A RECESS THEREIN, SENSING MEANS CARRIED BY SAID EXTRUSION STEM FOR SENSING THE CORRECT POSITION OF SAID DUMMY BLOCK, SAID SENSING MEANS INCLUDING A FIRST ROD SLIDABLE IN SAID EXTRUSION STEM, SAID FIRST ROD INCLUDING A PROJECTION AT ONE END THEREOF, MEANS FOR BIASING SAID FIRST ROD TO AN OUTWARD POSITION, SAID PROJECTION BEING ADAPTED TO FIT IN SAID RECESS WHEN SAID FIRST ROD IS IN SAID OUTWARD POSITION, SAID FIRST ROD ALSO INCLUDING A LATERALLY 